Tandem Tom

I am doing a ebike conversion for a friend. The frame is aTrek Antelope. The battery will be mounted on the DT. I would like to add 2 more mounting points to to make it more secure but don't want to mess up the nice paint. Wi using a RivNut compromise the DT?
Thanks!

unterhausen

It's not likely to hold.

Andrew R Stewart 

Rivnuts have a bad enough time dealing with the mass of a water bottle. Is the motor less weight? How does the motor react to its drive forces? How do the various mounting points deal with this vector? If the Rivnuts were positioned so that only shear forces are seen and there are no rocking forces than maybe enough Rivnuts could work, but I wouldn't trust it until a trial was done with enough miles/cycles to make me comfy. Andy

unterhausen

It's for batteries, not the motor, so there isn't a concern with torque. OTOH, I recently saw a pic where a battery just ripped out a batch of mount points. Most production ebikes don't use water bottle mounts at all.

Andrew R Stewart 

My mistake for not catching the battery mounting aspect. Still my concerns are much the same as Eric's.

Tom mentions adding additional mounts. I assume this is in addition to the factory bottle mounts. Steel or alloy frame (as in brazed in place bosses or compressed rivnut types)? Andy

Tandem Tom

Thanks for the replies. For perspective I Used Rivnuts on my ebike conversion, a Giant Escape,which is an aluminum frame. Have about 1400 as of yesterday. This is my commuter bike.

unterhausen

It won't compromise the dt until the rivnuts tear out. If you're convinced it will work, have at it.

wesmamyke

Get one of these mounts, and run the hose clamps. Most secure mounting I've done or seen. They come with some heat shrink for the clamps to protect the paint, I just used some rubber strips from a reflector set and it looks much better.

I have added a rivnut as well, it was okay. Still had to run the hose clamps, too much movement without them.

https://ebikes.ca/shop/electric-bicy...ouble-bob.html

https://ebikes.ca/shop/electric-bicy...riple-bob.html

Doug Fattic 

Wes's solution seems like a solid one. It would also be possible to drill holes on the other side of the tube so that the bosses being used could be attached with bolts going all the way through the tube. Of course there would need to be reinforcements around all the holes (probably made out of .058" wall tubing) to distribute the stresses over a wider area.

unterhausen

I like that clamp on mount. I'm wondering if I should get something like that laser cut to be brazed on.